McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 51. |
If D is the diameter of the sphere, then volumetric strain is equal to |
| A. | two times the strain of diameter |
| B. | 1.5 times the strain of diameter |
| C. | three times the strain of diameter |
| D. | the strain of diameter |
| Answer» C. three times the strain of diameter | |
| 52. |
If L be the length and D be the diameter of cylindrical rod, then volumetric strain of the rod is equal to |
| A. | strain of length plus strain of diameter |
| B. | strain of diameter |
| C. | strain of length plus twice the strain of diameter |
| D. | strain of length |
| Answer» C. strain of length plus twice the strain of diameter | |
| 53. |
the extension per unit length of the rod due to suddenly applied load as compare to same load gradually applied to same rod is |
| A. | same |
| B. | double |
| C. | three times |
| D. | half |
| Answer» B. double | |
| 54. |
The tensile force at a distance y from support in a vertical hanging bar of length L whch carries a load P at the bottom is equal to---- where w = weight per unit length |
| A. | p |
| B. | p+wl |
| C. | p+w(l-y) |
| D. | p+wy |
| Answer» C. p+w(l-y) | |
| 55. |
Total elongation produced in a bar due to its self weight is given by……….. Where ρ is the density of material in kg/m3 |
| A. | 9.81ρl2/e |
| B. | 9.81ρl2/2e |
| C. | 9.81ρl/e |
| D. | 9.81ρ2l/2e |
| Answer» B. 9.81ρl2/2e | |
| 56. |
The elongation of circular tapered rod is given by…………. Where P=axial pull and d1, d2= diameters at two ends. |
| A. | 4pl/πed1d2 |
| B. | 2pl/πed1d2 |
| C. | 4pl/ed1d2 |
| D. | 4p2l/ed1d2 |
| Answer» A. 4pl/πed1d2 | |
| 57. |
If a bar of length L m extends by l mm under load W, the strain is |
| A. | 1000 l/l |
| B. | l/l |
| C. | 0.001 l/l |
| D. | none of the above |
| Answer» C. 0.001 l/l | |
| 58. |
Four wires of same material are applied the same load. In which of the following cases, the elongation will be maximum (length, diameter)? |
| A. | 2m, 1mm |
| B. | 4m, 2mm |
| C. | 8m, 4mm |
| D. | 12m, 6mm |
| Answer» A. 2m, 1mm | |
| 59. |
If ES = 3 EA , the stress in steel of a composite bar made of aluminium and steel strips each having a cross sectional area of 300 mm2 and subjected to an axial load of 12 kN |
| A. | 10mpa |
| B. | 20mpa |
| C. | 30mpa |
| D. | 40mpa |
| Answer» C. 30mpa | |
| 60. |
The modulus of rigidity in terms of modulus of elasticity is given by |
| A. | e/2(1-γ) |
| B. | e/2(1+γ) |
| C. | 2e/(1-γ) |
| D. | 2e/(1+γ) |
| Answer» B. e/2(1+γ) | |
| 61. |
The modulus of elasticity in terms of bulk modulus is given by |
| A. | 3k/(1+2γ) |
| B. | 3k(1+2γ) |
| C. | 3k/(1-2γ) |
| D. | 3k(1-2γ) |
| Answer» D. 3k(1-2γ) | |
| 62. |
The ratio of Young's modulus and bulk modulus is given by |
| A. | 3/(1+2γ) |
| B. | 3(1+2γ) |
| C. | 3/(1-2γ) |
| D. | 3(1-2γ) |
| Answer» D. 3(1-2γ) | |
| 63. |
The modulus of elasticity in terms of bulk modulus and modulus of rigidity is given by |
| A. | 9kg/(3k+g) |
| B. | 9kg/(k+3g) |
| C. | (3k+g)/9kg |
| D. | (k+3g)/9kg |
| Answer» A. 9kg/(3k+g) | |
| 64. |
For a Poisson's ratio of 0.4 for a material the ratio of shear modulus of elasticity to modulus of rigidity is |
| A. | 14/5 |
| B. | 5/7 |
| C. | 7/5 |
| D. | 5/14 |
| Answer» D. 5/14 | |
| 65. |
A material has modulus of rigidity equal to 0.4x105 N/mm2 and Bulk modulus equal to 0.95 x105 N/mm2 The Young’s modulus value in GPa is.. |
| A. | 115 |
| B. | 105 |
| C. | 145 |
| D. | 175 |
| Answer» B. 105 | |
| 66. |
A bar of 30 mm diameter is subjected to an axial force 280 KN length of bar is 400 m and E= 200GPa. Determine volumetric strain if m=4. |
| A. | 1.46x10-3 |
| B. | 9.9 x 10-4 |
| C. | 2.9 x 10-3 |
| D. | 1.48 x 10-4 |
| Answer» B. 9.9 x 10-4 | |
| 67. |
A rail 20 m long is prevented from expansion at both end . If the temperature is raised by 30 0C, Stress induced in rail is.. E=200 Gpa,α =12x10-6/°C |
| A. | 24 mpa |
| B. | 48mpa |
| C. | 72mpa |
| D. | 94mpa |
| Answer» C. 72mpa | |
| 68. |
A tensile material is having Young’s modulus 2.1 x105 N/mm2 and modulus of Rigidity is 0.82 x105 N/mm2. The value of Bulk Modulus is .. |
| A. | 1.4 x105 n/mm2 |
| B. | 1.6 x105 n/mm2 |
| C. | 1.81 x105 n/mm2 |
| D. | 1.5 x105 n/mm2 |
| Answer» B. 1.6 x105 n/mm2 | |
| 69. |
A steel rod of length is manufactured at a temperature 200C and its temperature increases upto 1350C.What are thermal stresses induced? E=200Gpa,α=12*10-6/0C |
| A. | 312mpa |
| B. | 310mpa |
| C. | 320mpa |
| D. | 276mpa |
| Answer» D. 276mpa | |
| 70. |
A steel rod of 3m is manufactured at 250C the temperature of rod is increases to 1250C. If free expansion is 3.6mm, what is the temperature stresses produced if 1.5mm expansion is permitted? |
| A. | 100mpa |
| B. | 200mpa |
| C. | 150mpa |
| D. | 140mpa |
| Answer» D. 140mpa | |
| 71. |
A steel rod of 3m length is manufactured at 250C the temperature of this rod increases to 1250C. What is the free expansion? Take E=200Gpa, α=12*10-6/0C,diameter=12mm |
| A. | 3.2mm |
| B. | 2.6mm |
| C. | 4mm |
| D. | 3.6mm |
| Answer» D. 3.6mm | |
| 72. |
A steel tube (E = 200 GPa) has an internal diameter of 40 mm thickness 10 mm and a length of 2 m. If it is subjected to an axial pull of 80 kN, the stress in the tube will be __ _MPa. |
| A. | 28.3 |
| B. | 50.13 |
| C. | 84.88 |
| D. | 113.18 |
| Answer» B. 50.13 | |
| 73. |
A steel tube (E= 200Gpa) has an internal diameter of 40 mm, thickness 10 mm and a length of 2 m. If it is subjected to an axial pull of 80 kN, the change in length of the tube will be __ _mm. |
| A. | 0.283 |
| B. | 0.5 |
| C. | 0.85 |
| D. | 0.113 |
| Answer» B. 0.5 | |
| 74. |
The axial force in the portion AB of the member shown in Fig. 1.1 is kN. |
| A. | 50 |
| B. | -50 |
| C. | 40 |
| D. | -40 |
| Answer» A. 50 | |
| 75. |
If the member shown in Fig. 1.1 has a square cross section of 25 mm
|
| A. | 0.24 |
| B. | -0.24 |
| C. | 0.32 |
| D. | -0.32 |
| Answer» A. 0.24 | |
| 76. |
The axial force in the portion BC of the member shown in Fig. 1.1 is kN. |
| A. | 50 |
| B. | -50 |
| C. | 40 |
| D. | -40 |
| Answer» D. -40 | |
| 77. |
If the member shown in Fig. 1.1 has a
|
| A. | 0.16 |
| B. | -0.16 |
| C. | 0.24 |
| D. | -0.24 |
| Answer» B. -0.16 | |
| 78. |
The axially loaded composite rod shown in Fig. 1.2 has a uniform cross- sectional area of 500 mm 2 . The modulii of elasticity are Est = 200 GPa, Eal = 70 GPa and Ecu = 120 GPa. The change in length of CD is mm. |
| A. | 0.15 |
| B. | -0.15 |
| C. | 0.24 |
| D. | -0.24 |
| Answer» A. 0.15 | |
| 79. |
The axially loaded composite rod shown in Fig. 1.2 has a uniform cross- sectional area of 500 mm 2 . The modulii of elasticity are Est = 200 GPa, Eal = 70 GPa and Ecu = 120 GPa. The change in length of the composite rod is mm. |
| A. | 0.95 |
| B. | -0.95 |
| C. | 0.5 |
| D. | -0.5 |
| Answer» B. -0.95 | |
| 80. |
For the stepped rod shown in Fig. 1.3, the stress is maximum in . |
| A. | aluminum |
| B. | copper |
| C. | steel |
| D. | none of these |
| Answer» C. steel | |
| 81. |
For the stepped rod shown in Fig. 1.3,the in . |
| A. | aluminum |
| B. | copper |
| C. | steel |
| D. | none of these |
| Answer» A. aluminum | |
| 82. |
A steel bar ABC (E = 200 GPa) is 1 m long. For AB = 0.7 m, it has cross section P area of 500 mm2 and for BC = 0.3 m the cross section area is 400 mm2. The bar is subjected to an axial pull of 100 kN. The stress is maximum in ___ _ |
| A. | ab |
| B. | bc |
| C. | same throughout |
| D. | none of these |
| Answer» B. bc | |
| 83. |
A stepped bar of steel consists of a pmormtion with cross section area 500 mm2 connected to a portion with cross section area 1000 2. Each portion has a length of 1 m. The modulus of elasticity of steel is
|
| A. | 0.5 |
| B. | 0.75 |
| C. | 0.1 |
| D. | 0.15 |
| Answer» B. 0.75 | |
| 84. |
The change in length of a rod of uniform circular cross section was found to be 2 mm for some applied force. The change in length of a rod of the same material and length but of half the diameter subjected to the same force will be Mm |
| A. | 1 |
| B. | 2 |
| C. | 0.5 |
| D. | 4 |
| Answer» D. 4 | |
| 85. |
A strip of steel (E = 200 GPa, 0.25) has a length of 1 m, width of
|
| A. | 1000 |
| B. | 1000.25 |
| C. | 999.25 |
| D. | 0.25 |
| Answer» B. 1000.25 | |
| 86. |
The change in length of a rod of uniform cross section was found to be 2 mm for some applied force. The change in length of a rod of the same material and length but of twice the cross section area subjected to the same force will be__ mm. |
| A. | 1 |
| B. | 2 |
| C. | 0.5 |
| D. | 4 |
| Answer» A. 1 | |
| 87. |
Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces with magnitudes in the ratio 2 : 1. The stresses induced in the two rods will be in the ratio ____ _. |
| A. | 1 : 2 |
| B. | 2 : 1 |
| C. | 1 : 1 |
| D. | 4 : 1 |
| Answer» D. 4 : 1 | |
| 88. |
Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces with magnitudes in the ratio 1 : 2. The stresses induced in the two rods will be in the ratio ____ _. |
| A. | 1:1 |
| B. | 1:2 |
| C. | 1:1 |
| D. | 4:1 |
| Answer» C. 1:1 | |
| 89. |
Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces of the same magnitude. The stresses induced in the two rods will be in the ratio __ _ . |
| A. | 1 : 2 |
| B. | 2 : 1 |
| C. | 1 : 1 |
| D. | 4 : 1 |
| Answer» B. 2 : 1 | |
| 90. |
If an axial force of 15 kN is applied to a rod of 25 mm diameter, length 300 mm, the change in length of the rod was observed to be 0.045 mm. The modulus of elasticity of the material is 200 GPa. The strain in the rod will be ____ _. |
| A. | 1.5 |
| B. | 1.5*10-4 |
| C. | 1.33*10-3 |
| D. | 0.0455 |
| Answer» B. 1.5*10-4 | |
| 91. |
If an axial force of 1 kN is applied to a rod of 100 mm cross section area produces change in length of 1 mm over a length of 12 m, the modulus of elasticity of the material will be--------- |
| A. | 120mpa |
| B. | 10gpa |
| C. | 12gpa |
| D. | 120gpa |
| Answer» D. 120gpa | |
| 92. |
If an axial force of 1 kN is applied to a rod of 100 mm2 cross section area, length 5 m and the modulus of elasticity of the material is 100 GPa, the change in length of the rod will be ___ . |
| A. | 1mm |
| B. | 1.2mm |
| C. | 0.5mm |
| D. | 0.25mm |
| Answer» C. 0.5mm | |
| 93. |
The longitudinal stress developed in a rod of cross section area 50 mm2 is 100 MPa. The force acting along its axis is ------- |
| A. | 2n |
| B. | 2.5kn |
| C. | 5n |
| D. | 5.5kn |
| Answer» D. 5.5kn | |
| 94. |
If an axial force of 1 kN is applied to a steel rod of 100 mm2 cross section area, the stress in it will be ___ . |
| A. | 10mpa |
| B. | 10gpa |
| C. | 1mpa |
| D. | 1gpa |
| Answer» A. 10mpa | |
| 95. |
Two equal and opposite forces of magnitude 10 kN are applied at the ends of a steel wire to increase its length. The internal force in the wire will be-----KN |
| A. | 0 |
| B. | 10 |
| C. | 20 |
| D. | 15 |
| Answer» B. 10 | |
| 96. |
The value of factor of safety is always __ _. |
| A. | >1 |
| B. | <1 |
| C. | =1 |
| D. | =0 |
| Answer» A. >1 | |
| 97. |
The value of margin of safety is always __ _. |
| A. | >1 |
| B. | <1 |
| C. | =1 |
| D. | =0 |
| Answer» D. =0 | |
| 98. |
The radius of wire stretched by a load is doubled, then its Modulus of elasticity will be.. |
| A. | doubled |
| B. | halved |
| C. | becomes 4 times |
| D. | unaffected |
| Answer» D. unaffected | |
| 99. |
The factor of safety depends on
|
| A. | i) and ii) |
| B. | ii) and iii) |
| C. | i) , ii) and iii) |
| D. | iv |
| Answer» D. iv | |
| 100. |
The thermal stress is given by where α = coeffeicient of linear expansion T = Rise in temperature |
| A. | eαt |
| B. | et/α |
| C. | eα/t |
| D. | 1/eαt |
| Answer» A. eαt | |
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